The larvae of beewolf digger wasps are protected from pathogenic microbes thanks to bacterial symbionts.

"Beewolf digger wasps cultivate specific symbiotic bacteria (Streptomyces
spp.) that are incorporated into the larval cocoon for protection
against pathogens. We identified the molecular basis of this protective
symbiosis in the natural context and demonstrate that the bacteria
produce a 'cocktail' of nine antibiotic substances. The complementary
action of all symbiont-produced antibiotics confers a potent
antimicrobial defense for the wasp larvae that parallels the
'combination prophylaxis' known from human medicine." (Kroiss et al. 2010:261)